The Docker package is available via the EPEL repository. These instructions work for CentOS 6 and later. They will likely work for other binary compatible EL6 distributions such as Scientific Linux, but they haven't been tested.
Please note that this package is part of Extra Packages for Enterprise Linux (EPEL), a community effort to create and maintain additional packages for the RHEL distribution.
Also note that due to the current Docker limitations, Docker is able to run only on the 64 bit architecture.
To run Docker, you will need CentOS6 or higher, with a kernel version 2.6.32-431 or higher as this has specific kernel fixes to allow Docker to run.
使用EPEL软件仓库可以安装docker，版本必须在centos6 以后
如果是centos7
下载并安装这个软件包
wget http://mirror.hust.edu.cn/epel/beta/7/x86_64/epel-release-7-0.2.noarch.rpm
rpm -ivh
epel-release-7-0.2.noarch.rpm
如果是centos6
wget http://mirrors.hustunique.com/epel/6/i386/epel-release-6-8.noarch.rpm
rpm -ivh
epel-release-6-8.noarch.rpm
yum install docker-io 用上面这个命令安装就可以了
如果之前的系统中存在docker这个软件，最好先删除掉这个包，一个老旧的包
$ service docker start
$ chkconfig docker on